The Install Tool Password is not the admin password of TYPO3.
The default password is joh316. Be sure to change it!
If you don't know the current password, you can set a new one by setting the value of
$TYPO3_CONF_VARS['BE']['installToolPassword'] in typo3conf/LocalConfiguration.php to
the hash value of the password you desire. You can get the hash value of your password
by submitting the desired password with this form.